jparker



Feb. 19, 1929. A 1,702,917

J. EJPARKER MULTIPLE WAVE DETECTION AND TRANSMISSION APPARATUS Filed March 23, 1927 2 Sheets-Sheet 1 a L J VAR/A01: ma

LJ L 3 VMMBAE mo Fig. 2

James E Parker IN VEN TOR.

BY z y A TTORNEYS.

Feb. 19, 1929. 1,702,917

J. E. PARKER MULTIPLE WAVE DETECTION AND TRANSMISSION APPARATUS Filed March 23,- 1927 2 Sheets-Sheet 2 James 5 Parker INVENTOR.

BY/QLMQM A TTORNEYS.

Patented Feb. 19, 1929.

JAMES PARKER, OF WASHINGTON, DISTRICT OF COLUMBIA.

MULTIPLE WAVE DETECTION AND TRANSMISSION APPARATUS.

Application filed March 2-3,

My invention relates broadly to multiple wave transmitters and detectors and more particularly to the circuits used in each and in the apparatus constituting a combination of the two.

It is well known that the detection of radio signals transmitted by distant broadcasting stations is subject to interference caused by the response or" the detecting circuits to disturbances arising from nearby or powerful transmitting stations, from static and strays or from miscellaneous sources of energy radiation.

The loop receptor, the unidirectional receiver, loose coupled circuits in cascade, acceptor and rejector ,Ircuits, wavotraps, shielding and other methods of filtering; and obtaining directive and selective reception have been resorted to with results that have not been satisfactory.

The object of my invention is the production of circuit in which detection or transmission .may be accomplished with the re duction of extraneous int riterence to a minimum heretofore unattained.

Another object otmy invention is and novel method and means for accompi selective detection and amplification off signals consisting in part of utilizi w separately or in combin tion the addi .ivo and the substractive rr its and eii'c-cts of mutual inductance in coil system.

Further objects of my invention will appear more tally hereinafter as the description of the method and apparatus devcloped.

My invention-consists substantially in the construction, combination and arrangement of parts associated therewith or as will be more fully hereinafter set forth snown by the accompanying drawings and. finally pointed out in the appended. claims.

Reference is to be had to the accompany ing drawings forminga part of this spe ification in which like reference characte i indidicate corresponding parts throughout the several views and in. which:

Figure 1 is a circuit diagram of my invention as applied to a simple receiver circuit,

liigruro l is a modification thereof,

Figure 2 is a turther modification thereof,

Figure 8 is combined transmitter and n u S receiver circuit embodying the principles of my invention, and

. Figure i is a modification thereof.

It is known that two mductances, 1f

19?! Serial NO. 177,752.

brought into relationship with each other, may have total value of inductances greater than the sum of the two individual sections or that by reversing the position of one section, the total value of inductance may be less than that of the algebraic sum of the values of the two sections. This eil'ect is typical of: the functioning of a variometer in, which the reacting inductances are movable relative to each other. I

li ly invention covers the method and means for obtaining greater and lesser values of inductance without requiring a change in the position or relationship of the sections that comprise the coil system, and the utilization of this method and means for obtaining a signal free from undesirable interference, or the reduction to a minimum of the efi ect of such interference, with the highestdegree of ellicioncy consistent with simplicity of construction and operation.

Referrii articularly to Figures 1 and 1*, in which is shown a simple solenoid type or" inductance in combination with a capacity or .apacities, L designates a coil system in which the totalinductance is greater than that of the sum of the inductance of any two sections such as a-?) plus be, or a-0 plus o-c, each considered separately,

In parallel with the coil L are a plurality of condensers C and C connected in series. 'lhe electrical center of the condenser system connected to the electrical center or" the coil system by the connection 0-0. The grid 6 of the vacuum tube 1 is connected to the point e of the coil system or may be connected to the point'c ot the condenser system. The filament of the vacuum tube is connected to the point e of the condenser system; The plate of the vacuum tube is connected through the coil L through a source of plate current supply to the filament of the vacuum tube.

The circuit L (C plus C .is responsive to the frequencies to which it is tuned. This resonant cll'ect depends upon the LC; values involved, relative to the points upon the coil that are connected to the condensers.

\Vhen the circuit is tuned to resonance for a particular frequency points a and a will be at a particular instant, at equal and opposite potentials relative to each other. At the same given instant the potentials at points a and e are equal and opposite with respect to a midway point 0; points a and c are equal and opposite with respect to a midway point through 189 degrees referre'clto as the B frequency;

5; points 0 and c are equal and opposite with respect'to a midway point CZ; and points 3) and (Z are equal and opposite with respect-to a midway point 4;. l I V i fhen the inductance of the section a0 is equal to that of ce ancl'the. capacity of condenser C is equal to the capacity of condenser C the potentials at points 0' and 0 are equal and of like polarity at any given instan Points 0 and 0 'may therefore be connected together without any flow of current between the two. A switch 3 may be ineluded, as shown, to open or close this connection for securing certain vfunctions. tlescribed hereinafter.

in the following"description, the frequency at whit r the points a and e are equal and oppositefinpotential and polarity. will be reterrecl to as the A frequencm i hen the coil L" is excited. by a cu rent or the A frequency througheny well known meingsuch as by pe'city or inductive coupling to a suitable circuit, by the functioning oi the coils as loops, or by he: self-excited and oscillatin'g in conjunction with a vacuum tube circoupling to the coil L 7 The coil L is c 2 his of abort its axis from a position parallel to coil lr through a position at rig it engles thereto, nclto'a position parallel to the coil L but osite toits original position. 7 r

The plate 8 of Vacuum tube 1 is connected the filament-i of the vacuum through the coll-L end source of plate current supply.

' The filament hin turn, is connected to the point e on the coil l The grid may beconnectecl topoints a, o, c, or d, accordingtofthe tag-e desired. I t er iplanat-ion purposes only the gricl on n conne :tetl to the point e of the coil sysem I. lhe arrung einentot parts and the 'ustn rents oi the same are'such that the e at the A frequency rat a position parallel with arm viii oncrete between this 1g pos t-ion, her-clus er designated osition, sue the DOSIUOD approxii with the coil Lflthat is at 'otzero coupling. hen the'coil tween the and degree position 9H] w be found to be resonantu-t trequency uhe'her the si-aitch 3 is closed oropcr With all niai 11in quency other i switch is closed anti the coil L is in position between QOlIDCl 180 clog? es from the O position... This" frequency will 15" :2ina l'ter be The system as shown in Figure I is resorevolt tion quency if the of the switch 0. I have found further that the points a and 6 may or may not be con necterl togetl-ier without changing the B frequency; This I have accomplished by menus of the connection a-c in which there is a switch 10.

i owever, it the points a and e ur-e connected tog r by the wires 4: and 5 and the switch 10, the system is nonrcsonant to the A frequency. Thus, referring to Figure 1, it the switches 8 and 10 are open the system is resonant to the it frequency. It the switches 8 and. 10 are closed the system is resonant to the B frequency.

By means of this errangemcnt it is possib'c to reduce to a minimum tendency oi? the coil system L to respond to energy other than that transmittec through the medium oi? the coi L at the B frequency. By closing; the switch 10 I remove the tendency of the coil and vacuum tube combination to respond to, regenerate, or oscillate at the A frequency, the tender c y of the coil system L tunctionin as a loop being to respontl to signals of the B frequency and to be practically non-resonant to frequencies slightly removed from that frequency.

When the points a and 'e are connected together, they are at the some potential with resheet to each other but both points are at an equal and opposite the points 0 an-cl In the position shown in Fi L will impart one u equally ections o-c and e-c of coil syst ui L i h the points (I, unil'e conn clefl t nether, the CD11 system a: a will not respond 11 cu en oi either the A? or the B frequency 'nnsinittcrl b:- coil if. It the switch it) opened, J

tern by reason of the tight mmpliua her 7 r T the c is L and it will respond 2 currents (7 t 7, B ii'i'lfllitlill) uh;

or the A Ercqueiicy in the coil L ie switch 10 open or closed I the desired amountci ene y of the A irequency in the coil l may be trunsinittt to the coil system (4+0 by changing the poci 'on of the coil L with. respect to the electrical center of the coil system oe shown. by the arrow 11. The circuit disclosed inFig'ure 1 open ates in similar manner but by the transfer of current from the coil L to the coil system as-e is of the B frequency.

two addition; its are conn frequency between coil ll :1 nd coil s" c-c, and have substituted a capacity C in the place of the switch 10 of Figure 1. The fro inductance L does not affect th- A quency and the capacity C does not a the B frequency for the reason that l ected across nodal po nts of the respective circi However, the value of the A frequency is eli'ected by the capacity factor C Also the value of the B frequency is effected by the inductance factor If. Although shown as inductance and capacity it will be understood that the units may be inductances or capacities or combinations of both.

Since in the coil. system L the points a. and c. are connected together in such a manner that the B frequency and not the A frequency will prevail, the system responds as desired to the energy received from coil If. f coil If in the plate circuit of a vacuum tube am plifier, it should. or "'3 l3 frequency only. This requires that the grid of the vacuun'i tube amplifier should receive energy at B frequency only. Figure 2 shows one type of arrangement by which this result may be accomplished. The antenna-ground circuit is shown tightly coupled to coil system a@ with respect to the A frequency, and in the A frequency. Coupled to coil If is a tuned B frequency circuit consisting of an inductance L with a tuning condenser C in parallel therewith which constitutes the input of a detector or amplifying circuit as desired.

It is known that most undesirable interferences arise from. damped oscillatory discharges and shock excitations, such as static, strays and other caus s. Due to the tight coupling between coil L and coil system L at the A frequency, the shock or damped energy will cause coil system L to oscillate at the A frequency but this excitation does not affect the coil L. 13y reason of the effective loose coupling at the 13 stein. If. the latter will respond at the B frequency to the H 'i'i'cmieiicy energy received. by the auteuiui system. This response will hetransmitted through the medium of coil L to the detector or amplifier circuit coupled to coil In. Spurious excitations of the antenna sys' tem that cause it to oscillate at the A frequency, the period predeterminedby the of feet of the tight coupling to the coil system L at this A frequency, will not be transmitted to the coil L and the detector or amplifier circuit coupled thereto. In this man- .ner the detection or amplification of nude sired interferences of whatever kind. or type is reduced to a minimum. 1 7 Separation of the values of the and the 5 frequencies is accomplished l y vary ing the separation of the two halves ((4-0 and. a e) of inductance coil system o@ and also by adjusting the values of the units, if'any, between points 0 and 0 and points a and 6.

Referring to Figure 1', tl e current flow at the B frequency being equal and in opposite directions in the two halves of the coil system ae, if such a coil system is to. be used as an oscillator at the B frequency, the opposing fields tend to neutralize undesirable.

effects of coupling to separate, distinct and distant circuits. In this manner interfercncecaused by the function of the coil system a@ as a generator and transmitting or 'adiating energy is eliminated. In the Figures 1 and 2 the elimination of e:-;traneous disturbances is accomplished, if the coil system be an oscillator at the A frequency.

Further modifications are shown in Figures 3 and 4 the detail operation and construction of which are considered obvious from the foregoing description of the simple circuit.

Referring to Figure 3, 1 represents'a vacuum tube oscillating at the A frequency and 2 represents a vacuum tube so arranged that it detects at the B frequency. The grid 6 of vacuum tube 2 is connected to coil L through variable connection 12 which 0011- I trols the potential upon the grid 6.

Figure 4 represents a circuit in which vacuum tube 1 is oscillating at the B frequency and Vacuum tube 2 is detecting at the A frequency.

Either of the circuits shown in Figures 3 and 4c are adaptable to either simultaneous reception and transmission of signals or may be used in heterodyne reception, the frequnecy of the resultant long wave being the difference in frequency between the A and B frequency.

Asan alternative the filament may be connected to corresponding potential points of the coil system a-e instead of to the condenser system as shown, without affecting the functioning of the system. Also one tube may function as an oscillator on one freuency while the other tube operates as a detector upon the other tlrequency.

In any of the circuits disclosed all of the tubes are capable of functioning at two frequencies in the following manner.

In Figures 1, 1" and 2 the one tube may act as a detector at one frequency and simulta neously as an oscillator at the other frequency, detect at both frequencies orv oscillate at both frequencies. In the circuits shown in Figures 3 and t one tube may be substituted for the two tubes to obtain the results heretofore described by merely using the well known methods OPE blocking or lay-passing,

the alternating and .direct-currents'in the circuit as required.

It will be understood that the shove de-* scription and accompanying drawings comprehend only the general and preferred cin- -bocliment of my invention and that minor detail changes in the construct onandsrranceinent of arts me I be made Within the U r V ions, condensers in par allel with each section and means for regeneration at the resonant frequency of the tire system and for rQQBllQTZtt-lOH at the resoto the system and variably coupied entire system, the said in s coinpr'isln a coil coupled to the entire system and rotatsole through 180 degre y t m. $2; In coinl "tion, at coil system coniprising a plurality of sections, at cond nser in parallel with each section, said sections being inductively coupled together to p:oduceev 1oircuit resonant at a plurality of frequencies, vacuum tube, the electrodesof which are connected to the coil system at plurality of points, and an input coil i ductively coupled with reference to the sections to ectivate the vacuum tube at a single resonant.lrcquency oi the coil system; i V v c in combination, a coil system comprising a plurality of sections, a condenser in parallel with each section, said sections being inductively coupled together to produce a cuit resonant at a plurality of frequencies, a vacuum tube, the ElQCIt'Z'GQlQS'OZE-WlllCll are connectedtothe coil sy; .11 at a plurality points, and an input coi J of coupling with the coil tube at the frequency determined by the addi coil system compr'is V l inductively coupled to the system and variably coupled with refcrence to the sections to activate the vacuum 4. In combination, a coil system comprisng a plurality .01" sections, a condenser in rallel with each section, said sections be-i-n inductively coupled together to produce a circuit resonant at a plurality of frequencies, a vacuiuntube, the electrodes of which ere connected to the i1 system at a plurality of points, and an input coil inductively coupled to the system and variably coupled with retto the sections to activate the vacuum tube at the "trequeney determined by the subtractive inductance of the sections.

5. In coin nation, a coil system comprisa plurality t sections, a condenser in parallel with each section, s id sections being inductively coupled together to produce a circuit resonant-at a plurality of tl requencies, s rcsoonsive to high frequency connected to i 1 system u plurality of points, and an input coil i .duct-ivc-ly coupled to the systcn'i and varia-b coupled with l crcnce to sections to activate said means at a ngle resonant frequency ct thesys iem.

'6. In com-l ution, a coil system comprisa plurality of sections, a condenser in ecrallel with each section, said sections being uctirely coupled together to produce a -1lCult resonant at u plurality of frequencies, inc-ans responsire to high frequency currents connected to said system a plurality of points, and an input coil inductively cou sled to the system and variably coupled with retthe sections to activate said means at plurality of frequencies.

7. in combination, a coil systei'n co1npri.'- a plurality of sections, a condenser in parl el with each section, said sections being inctivelv. coupled tocethcr to produce a circn o resonant at pl rality frequencies, 1

means responsive to l igh frequency currents connected to said svstein at a plurality of points. input coil inductively coupled to the sy and van ly coupled Wlill ret- 3'1 MES l1 PAR-YER. 

